Ever wonder why a Muslim is allowed
by Allah, Subhanuhu wa-Taala, to get sick?

Hadith – Bukhari 7:564
I visited Allah’s Apostle (Sall’Allahu alaihi wasallam) while he was suffering from a high fever. I touched him with my hand and said, “O Allah’s Apostle! You have a high fever.” Allah’s Apostle (Sall’Allahu alaihi wasallam) said, “Yes, I have as much fever as two men of you have.” I said, “Is it because you will get a double reward?” Allah’s Apostle (Sall’Allahu alaihi wasallam) said, “Yes, no Muslim is afflicted with harm because of sickness or some other inconvenience, but Allah will remove his sins for him as a tree sheds its leaves.”

Hadith – Muslim & Bukhari
Abu Sa’id al-Khudri r.a. reported that the Prophet (Sall’Allahu alaihi wasallam) said: Whenever a Muslim is afflicted with a hardship, sickness, sadness, worry, harm, or depression –even a thorn’s prick, Allah expiates his sins because of it.

Recorded by Bukhari in al-Adab ul-Mufrad (no. 493), verified authentic by al-Albani
“Expect good, because Allah (s.w.t.) makes a believer’s sickness an expiation (for his sins) and a period of repose. As for a disbeliever falling sick, he is like a camel whose owner ties it and then lets it loose –it does not understand why it was tied, nor why it was freed.”

The cure
Hadith – Sahih Bukhari, Book 25, Number 5466, Narrated Jabir ibn Abdullah May Allah be pleased with him
Allah’s Messenger (Sall’Allahu alaihi wasallam) said: There is a remedy for every malady, and when the remedy is applied to the disease it is cured with the permission of Allah, the Exalted and Glorious.
Hadith – Muwatta 50:12

Yahya related to me from Malik from Zayd ibn Aslam that a man received a wound in the time of the Messenger of Allah (Sall’Allahu alaihi wasallam). The blood clotted in the wound and the man called two men from the Banu Ammar tribe. They looked at it and claimed that the Messenger of Allah (Sall’Allahu alaihi wasallam) said to them, “Which of you is the better doctor?” They said, “Is there any good in medicine, Messenger of Allah?” Zayd claimed that the Messenger of Allah (Sall’Allahu alaihi wasallam) said, “The one who sent down the disease sent down the remedy.”
Narration – Ahmad
“Worshippers of Allah, use medical treatments.”
Hadith – Al-Tirmidhi #2170, Narrated Abdul Malik ibn Umayr May Allah be pleased with him
Allah’s Messenger (Sall’Allahu alaihi wasallam) said, “Fatihat al-Kitab contains healing for every disease.”
[Darimi and Bayhaqi, in Shu’ab al-Iman, transmitted it.]

Severe Trials for those Firms in their Religion

Hadith – Al-Tirmidhi 1562, Narrated Sa’d May Allah be pleased with him

When the Prophet (Sall’Allahu alaihi wasallam) was asked which people suffered the greatest affliction, he replied, “The prophets, then those who come next to them, then those who come next to them. A man is afflicted in keeping his religion. If he is firm in his religion his trial is severe, but if there is weakness in his religion it is made light for him, and it continues like that till he walks on the earth having no sin.”
[Tirmidhi, Ibn Majah, and Darimi transmitted it, and Tirmidhi said this is a Hasan sahih tradition.]

Rewards for those Afflicted
Hadith – Al-Tirmidhi #1570, Narrated Jabir ibn Abdullah May Allah be pleased with him

Allah’s Messenger (Sall’Allahu alaihi wasallam) said, “On the Day of Resurrection when people who have suffered affliction are given their reward, those who are healthy will wish their skins had been cut to pieces with scissors when they were in the world.”
[Tirmidhi transmitted it, saying that this is a gharib tradition.]

Recorded by Ahmad May Allah be pleased with him, verified authentic by al-Hakim, ath-Thahabi, and al-Albani
The ailment is intensified for the righteous. Whenever a believer is afflicted with a hardship, be it a thorn or more, a sin is taken off him because of it, and he is elevated on level (in Jannah [Paradise]).

Hadith – Al-Bukhari
A traveler’s or sick person’s deeds are recorded in accordance with what he used to do when he was a resident or well.

Endurance
Hadith – Al-Tirmidhi, Narrated AbuUmamah May Allah be pleased with him [Ibn Majah transmitted it.]

The Prophet (Sall’Allahu alaihi wasallam) stated that Allah, The Blessed and Exalted, says,
“Son of Adam, if you show endurance and seek your reward from me in the first affliction, I shall be pleased with no lesser reward than Paradise for you.”

Hadith – Sahih Bukhari, Muslim, and Nasa’i, Narrated ‘A’ishah may Allah be pleased with her The Prophet of Allah, upon him be peace, said, “Do not say, ‘I feel rotten*.’ Instead, say, ‘I do not feel well.”
*or any expression that involves corruption of any type.

Kindness to the sick
Hadith – Mishkat, Narrated Abu Sa’id May Allah be pleased with him

Allah’s Messenger (Sall’Allahu alaihi wasallam) said, “When you go in to visit an invalid, express a hope that he will live long. That will not avert anything, but it will comfort him.”

Hadith – Sahih Bukhari, Volume 8, Book 73, Number 40, Narrated An-Nu’man bin Bashir May Allah be pleased with him

Allah’s Apostle (Sall’Allahu alaihi wasallam) said, “You see the believers as regards their being merciful among themselves and showing love among themselves and being kind, resembling one body, so that, if any part of the body is not well then the whole body shares the sleeplessness (insomnia) and fever with it.”
Visit the sick

Hadith – Qudsi 18

O son of Adam, I fell ill and you visited Me not. He will say: O Lord, and how should I visit You when You are the Lord of the worlds? He will say: Did you not know that My servant So-and-so had fallen ill and you visited him not? Did you not know that had you visited him you would have found Me with him? O son of Adam, I asked you for food and you fed Me not. He will say: O Lord, and how should I feed You when You are the Lord of the worlds? He will say: Did you not know that My servant So-and-so asked you for food and you fed him not? Did you not know that had you fed him you would surely have found that (the reward for doing so) with Me? O son of Adam, I asked you to give Me to drink and you gave Me not to drink. He will say: O Lord, how should I give You to drink when You are the Lord of the worlds? He will say: My servant So-and-so asked you to give him to drink and you gave him not to drink. Had you given him to drink you would have surely found that with Me.